The present invention concerns a method of continuously introducing an impregnating liquid into a textile fiber arrangement.
The term "fiber arrangement" is to be understood as comprising natural as well as manmade staple fibers, such as produced as a continuous untwisted arrangement, e.g., as card sliver or drawframe sliver or as web at the delivery side of the drafting arrangement. This term also is understood to comprise bundles or strands of endless filaments.
The term "liquid," in the singular or plural, is to be understood to comprise water or solvents or any solutions, dispersions and emulsions of any materials (e.g., adhesives, dyestuffs etc.) in water and/or other solvents.
The term "impregnate" is to be understood to comprise the coating of the individual fibers or the individual filaments respectively of the fiber arrangement with a film of liquid as well as a homogeneous, fine droplet-type distribution of the liquid in the fiber arrangement or a combination of both.
From U.S. Pat. Nos. 3,323,176 and 3,426,389 methods and devices are known for treating a fiber arrangement with liquids by means of a pair of discs in which liquid is brought into a throughpassing fiber arrangement transformed into tubular shape via a coaxially arranged separate duct, and in an adjacent free zone the liquid is allowed to radially penetrate the fiber arrangement without hindrance. The fiber sliver thus imbued with liquid then passes through a room or space converging in the direction of the throughpassage fiber sliver and formed by a pair of discs and by lateral walls and finally is condensed into a compact fiber sliver in a hydrodynamic pressure zone acting omnidirectionally, i.e., at all sides of the fiber sliver with high specific pressure.
By means of such procedure homogeneous impregnating or liquid distribution respectively is achieved in the fiber sliver. However, this procedure has disadvantages. The converging space as well as the adjacent pressure zone are formed by the pair of discs and by lateral cover walls or plates arranged at the face sides or end faces of the pair of discs. In spite of careful design aimed at keeping the clearance between the disc face sides and the lateral cover walls as small as possible, frequent penetration of fibers cannot be avoided due to the extraordinary fineness of the fibers and thus the passing fibers jam between the discs and their cover walls. This effect is further intensified by the high specific pressure prevailing in the pressure zone. As the condensed fiber sliver leaves the cover walls so-called "moustaches" or fiber beards form and which consist of previously jammed fibers, which often causes disturbances in the operation. By further reducing the clearances between the faces of the pair of discs and the lateral cover walls temporary improvement is reached, but due to the excessively small clearance wear of the discs and/or the lateral walls is considerably increased and the condition described above of the fibers being caught is found anew. It also has been found that the total clearance between discs and lateral walls no longer is distributed evenly, if the smallest practically unavoidable imprecisions are present, i.e., a larger clearance prevails on one side of a disc than on the opposite side. Fiber jamming between the discs and their cover walls thus is further facilitated, and the achievement of a uniform condensation of the fiber mass in the pressure zone thus is highly questionable.